It might sound counterintuitive to add an expense in order to save more on travel, but you can actually access hidden discounts by booking more than just a flight, at least with British Airways. Independent Traveler writer Jamey Bergman saved $1,400 by adding a car rental to his flight.

British Airways says that when you select a package option (flight plus car or flight plus hotel), they then sell the package as a tour operator, with preferential rates passed on to you. Testing this myself for a round-trip flight from New York to London, adding a car rental shaved almost $500 off the price of the plane ticket alone.

This may or may not apply for other airlines or perhaps travel sites as well. I briefly tried a few other airlines (American Airlines, United) to see if they had similar secret package savings, but didn't see the same flight-plus-car rental search. (American Airlines, Expedia, and other travel sites do advertise savings if you combine hotel and airfare—but the savings isn't the same.) Still, it's worth a try when booking your next trip to compare the cost of a package with just the airfare alone, just in case. You might be pleasantly surprised.